Vagal Tone and Proinflammatory Cytokines Predict Feeding Intolerance and Necrotizing Enterocolitis Risk.

Background: Necrotizing enterocolitis (NEC) is the leading cause of death due to gastrointestinal disease in preterm neonates; yet, clinicians lack reliable and noninvasive predictive tools.

Purpose: We aimed to test that diminished high-frequency heart rate variability (HF-HRV) and elevated levels of proinflammatory cytokines would have utility in NEC prediction.

Methods: In this multisite prospective study, we enrolled 250 preterm (26-34 weeks' postmenstrual age [PMA]) neonates with physiological stability at 72 hours of life.

Necrotizing enterocolitis: It's not all in the gut.

Unlabelled: Necrotizing enterocolitis is the leading cause of death due to gastrointestinal disease in preterm neonates, affecting 5–12% of neonates born at a very-low birth weight. Necrotizing enterocolitis can present with a slow and insidious onset, with some neonates displaying early symptoms such as feeding intolerance. Treatment during the early stages includes bowel rest and careful use of antibiotics, but surgery is required if pneumoperitoneum and intestinal perforation occur.

Ghrelin ameliorates the phenotype of newborn rats induced with mild necrotizing enterocolitis.

Background: We have shown previously that an attenuated rodent model of mild necrotizing enterocolitis (NEC) increases intestinal histopathological severity grade, prevents typical developmental increases in the high-frequency spectrum of heart rate variability (HF-HRV), alters the nitrergic myenteric phenotype, and increases IL-6 and IL-1β when combined with anterior subdiaphragmatic vagotomy. The aims of the present study were to test the hypotheses that in mild NEC-induced pups, administration of the orexigenic hormone ghrelin (a) reduces the histopathological score, (b) increases the HF-HRV power, (c) improves the altered myenteric phenotype, and (d) subdiaphragmatic vagotomy prevents the effects of ghrelin.

Methods: Newborn Sprague Dawley rats were subjected to seven days of brief periods of cold stress and hypoxia to induce mild NEC with or without anterior subdiaphragmatic vagotomy.

Correlation between the motility of the proximal antrum and the high-frequency power of heart rate variability in freely moving rats.

Background: Cardiac vagal tone can be monitored non-invasively via electrocardiogram measurements of the high-frequency power spectrum of heart rate variability (HF-HRV). Vagal inputs to the upper GI tract are cumbersome to measure non-invasively. Although cardiac and GI vagal outputs arise from distinct brainstem nuclei, the nucleus ambiguus, and the dorsal motor nucleus of the vagus, respectively, we aim to test the hypotheses that in freely moving rats HF-HRV power is correlated to proximal antral motility and can be altered by high levels of circulating estrogen and vagal-selective treatments known to affect antral motility.

Necrotizing enterocolitis attenuates developmental heart rate variability increases in newborn rats.

Background: We have shown previously that a decreased high-frequency spectrum of heart rate variability (HF-HRV), indicative of reduced vagal tone, shows promise in predicting neonates likely to develop necrotizing enterocolitis (NEC) before its clinical onset. We hypothesized that NEC induction in rat pups decreases HF-HRV power; subdiaphragmatic vagotomy worsens the severity of the NEC phenotype, increases levels of pro-inflammatory cytokines, and alters the myenteric phenotype.

Methods: Newborn Sprague-Dawley rats, representative of preterm human neonates, were subjected to 7-8 days of brief periods of cold stress and hypoxia to induce NEC with or without unilateral subdiaphragmatic vagotomy.